diff --git a/doc/json_schema.json b/doc/json_schema.json
index 01f05602d..6391b2b79 100644
--- a/doc/json_schema.json
+++ b/doc/json_schema.json
@@ -302,9 +302,10 @@
                     "default": 2
                 },
                 "sizeMaxPrefix": {
-                    "type": "integer",
-                    "title": "Set the largest binary prefix to use when formatting sizes. 0 is B; 1 is KB; 2 is MB; etc.",
-                    "default": 255
+                    "type": "string",
+                    "title": "Set the largest binary prefix to use when formatting sizes",
+                    "enum": ["B", "kB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB"],
+                    "default": "YB"
                 },
                 "percentType": {
                     "type": "number",
diff --git a/src/common/jsonconfig.c b/src/common/jsonconfig.c
index 4b6d09546..3fa6fe37f 100644
--- a/src/common/jsonconfig.c
+++ b/src/common/jsonconfig.c
@@ -389,7 +389,23 @@ const char* ffParseDisplayJsonConfig(void)
         else if (ffStrEqualsIgnCase(key, "sizeNdigits"))
             config->sizeNdigits = (uint8_t) yyjson_get_uint(val);
         else if (ffStrEqualsIgnCase(key, "sizeMaxPrefix"))
-            config->sizeMaxPrefix = (uint8_t) yyjson_get_uint(val);
+        {
+            int value;
+            const char* error = ffJsonConfigParseEnum(val, &value, (FFKeyValuePair[]) {
+                { "B", 0 },
+                { "kB", 1 },
+                { "MB", 2 },
+                { "GB", 3 },
+                { "TB", 4 },
+                { "PB", 5 },
+                { "EB", 6 },
+                { "ZB", 7 },
+                { "YB", 8 },
+                {}
+            });
+            if (error) return error;
+            config->sizeMaxPrefix = (uint8_t) value;
+        }
         else if (ffStrEqualsIgnCase(key, "percentType"))
             config->percentType = (uint32_t) yyjson_get_uint(val);
         else if (ffStrEqualsIgnCase(key, "noBuffer"))
diff --git a/src/data/config_user.txt b/src/data/config_user.txt
index 2128c51a2..e9a481727 100644
--- a/src/data/config_user.txt
+++ b/src/data/config_user.txt
@@ -159,10 +159,10 @@
 #--size-ndigits 2
 
 # Size max prefix option:
-# Sets the largest binary prefix to use when formatting sizes. 0 is B; 1 is KB; 2 is MB; etc.
-# Must be an possitive integer.
-# Default is 255 (unlimited).
-#--size-max-prefix 255
+# Sets the largest binary prefix to use when formatting sizes.
+# Must be one of B, kB, MB, GB, TB, PB, EB, ZB, YB
+# Default is YB.
+#--size-max-prefix YB
 
 # Disable output buffer option:
 # Sets if the stdout application buffer should be disabled.
diff --git a/src/data/help.txt b/src/data/help.txt
index fdc21004a..78af50b05 100644
--- a/src/data/help.txt
+++ b/src/data/help.txt
@@ -66,7 +66,7 @@ Display options:
     --percent-type <value>:      Set the percentage output type. 1 for percentage number, 2 for bar, 3 for both, 6 for bar only, 9 for colored number. Default is 1
     --no-buffer <?value>:        Set if the stdout application buffer should be disabled. Default is false
     --size-ndigits <value>:      Set the number of digits to keep after the decimal point when formatting sizes
-    --size-max-prefix <value>:   Set the largest binary prefix to use when formatting sizes. 0 is B; 1 is KB; 2 is MB; etc.
+    --size-max-prefix <value>:   Set the largest binary prefix to use when formatting sizes. Default is YB
 
 General module options:
     --<module>-format <format>:    Set the format string to use for each specific module.
diff --git a/src/fastfetch.c b/src/fastfetch.c
index 94453774b..c83718fa9 100644
--- a/src/fastfetch.c
+++ b/src/fastfetch.c
@@ -918,7 +918,20 @@ static void parseOption(FFdata* data, const char* key, const char* value)
     else if(ffStrEqualsIgnCase(key, "--size-ndigits"))
         instance.config.sizeNdigits = (uint8_t) ffOptionParseUInt32(key, value);
     else if(ffStrEqualsIgnCase(key, "--size-max-prefix"))
-        instance.config.sizeMaxPrefix = (uint8_t) ffOptionParseUInt32(key, value);
+    {
+        instance.config.sizeMaxPrefix = (uint8_t) ffOptionParseEnum(key, value, (FFKeyValuePair[]) {
+            { "B", 0 },
+            { "kB", 1 },
+            { "MB", 2 },
+            { "GB", 3 },
+            { "TB", 4 },
+            { "PB", 5 },
+            { "EB", 6 },
+            { "ZB", 7 },
+            { "YB", 8 },
+            {}
+        });
+    }
     else if(ffStrEqualsIgnCase(key, "--percent-type"))
         instance.config.percentType = ffOptionParseUInt32(key, value);
     else if(ffStrEqualsIgnCase(key, "--no-buffer"))